#!/usr/env/bin bash

set -e
# set -x # For debugging

# If you ever mess this up:
#  $ mknod /dev/loop-control c 10 237
#  $ chmod 600 /dev/loop-control
#  $ chown root:root /dev/loop-control
#
# For cleanup:
#  $ find /dev -maxdepth 1 -type b -name 'loop[0-9]*' -exec rm -f {} \;

if [ "$(id -u)" -ne 0 ]; then
    echo "Run as root. We need permissions to write and setup a loop device."
    exit 1
fi

DISKFILE="/tmp/disk.img"
BINFILE="/tmp/file.bin"
LOOPNUM=$((RANDOM % 156 + 100))
LOOPDEV="/dev/loop${LOOPNUM}"

echo "Using device: ${LOOPDEV}"

cleanup() {
    echo "Cleaning up..."
    set +e -x
    losetup -d ${LOOPDEV}
    rm ${LOOPDEV}
    rm ${BINFILE} ${DISKFILE}
}

trap cleanup EXIT INT TERM

if losetup ${LOOPDEV} >/dev/null 2>&1; then
    echo "${LOOPDEV} already in use" >&2
    cleanup
    exit 1
fi

if [ ! -f ${DISKFILE} ]; then
    echo "Creating ${DISKFILE}"
    dd if=/dev/zero of=${DISKFILE} bs=1M count=256
fi

if [ ! -f ${BINFILE} ]; then
    echo "Creating ${BINFILE}"
    dd if=/dev/urandom of=${BINFILE} bs=1M count=64
fi

if [ ! -e ${LOOPDEV} ]; then
    mknod ${LOOPDEV} b 7 ${LOOPNUM} # busybox needs this
    losetup ${LOOPDEV} ${DISKFILE}
fi

./writeimg -nd ${LOOPDEV} ${BINFILE}
./writeimg -vnd ${LOOPDEV} ${BINFILE}

./writeimg -nd ${LOOPDEV} ./writeimg
./writeimg -vnd ${LOOPDEV} ./writeimg

./writeimg -nd ${LOOPDEV} ./LICENSE
./writeimg -vnd ${LOOPDEV} ./LICENSE

# Redirect this to avoid confusion
! ./writeimg -vnd ${LOOPDEV} ./crc32.h 2>/dev/null

GREEN="\e[32m"
RESET="\e[0m"

echo -e "\n\n${GREEN}Looks good!${RESET}"